Graphite, for example as one or more graphene sheets, is today an element led to play an essential role in the field of microelectronics or also spintronics. In order to obtain a good quality graphite layer, several techniques have been contemplated. It is in particular known to produce a graphite layer from a silicon carbide substrate. For this, it is necessary to heat the substrate at a temperature higher than the dissociation temperature of the silicon carbide. Indeed, during such a heat treatment, a graphite layer is formed at the surface of said substrate, the thickness of this layer depending on the duration of the heat treatment and the temperature applied to the substrate. It has also been shown that it was possible to resort to such a method with an aluminium carbide substrate with higher treatment temperatures. On the other hand, to date, there is no technique enabling, using, a heat treatment, graphite to be made on a so-called interstitial carbide layer, that is a carbide for which the carbon atoms are inserted in the interstices between metal atoms such as Titanium (Ti), Zirconium (Zr), Hafnium (Hf), Vanadium (V), Niobium (Nb), Tantalum (Ta), Chromium (Cr), Molybden (Mo) or Tungsten (W). Further, the dissociation temperature of such a carbide is very high, therefore a similar method would thus imply the use of very high temperatures, which raises problems in terms of manufacture and energy cost.
The issue of obtaining a good quality graphite layer is not the only difficulty encountered in manufacturing graphite based devices. It is also difficult to make electrical contacts enabling a graphite layer to be electrically connected. In order to define such contacts, it is known to deposit a metal layer at the surface of the graphite layer to be contacted and then to structure the metal layer in order to form one or more contacts. But, although an electrical connection is established by this technique, the latter is very often of a poor quality. In other words, a high electrical resistance exists between the metal layer forming the contact and the graphite layer desired to be contacted. In order to improve the quality of these contacts, it is therefore known to perform surface treatments as for example described in H. Y Park and AI's article, Adv. Mater. 28, 864 (2016), which imposes further method steps which are often complex. Moreover, as previously discussed, it is also necessary to structure the metal layer in order to form the different connections. These different requirements raise difficulties both in terms of cost and in terms of industrialization, since the methods used are very difficult to transpose in an industrial production environment.
There is thus a need for a method enabling a graphite layer to be obtained on an interstitial carbide layer by heat treatment. There is also a need for a method enabling a graphite layer to be contacted which does not require a complex and expensive surface treatment operation.